From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D27B4C11F66 for ; Wed, 14 Jul 2021 09:16:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ADDC761369 for ; Wed, 14 Jul 2021 09:16:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238442AbhGNJS6 (ORCPT ); Wed, 14 Jul 2021 05:18:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45506 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238144AbhGNJS5 (ORCPT ); Wed, 14 Jul 2021 05:18:57 -0400 Received: from mail-pl1-x62e.google.com (mail-pl1-x62e.google.com [IPv6:2607:f8b0:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B389CC06175F; Wed, 14 Jul 2021 02:16:05 -0700 (PDT) Received: by mail-pl1-x62e.google.com with SMTP id n11so1198241plc.2; Wed, 14 Jul 2021 02:16:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dqq4wN8QDeSEWFTLSBBUZmKIr6mpKClIb1WpfjF4Q+k=; b=aey7v3ZOh0MMLYdfNMzqu7PRcBUY9yKTzJJH31SWAuZLDkQl/tQTyn7PoOHZVjJ5PT 56hwXO5GPv9kJuZkX2xWwjwGaM3jeA3GQn2Ed5C2UJxeM7nCaZlcVh6QR888IrImrOFu M5Sahu2IcIgTqekEjquz6uU5wHjreJ3nmy4dzRTAV7/Zn1lihSeHoCtNn6jAfgpgIedG /af5TCZMjs6MYEO9A9HpgiqSDnfjqIv/jJDF3tNBuHTy+Rt0VaE0sINEGg7kVEXsRv/S 2gzH4x1XgP4j9FcIIyG4WcSMbsx3s1rks0u8P7gncYakhENIOjeav4ymEv8BOJtqVh6j Gp+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dqq4wN8QDeSEWFTLSBBUZmKIr6mpKClIb1WpfjF4Q+k=; b=bb1xp969snCG98C52dWCSCsRDVCgJL+lPSGwD08om0bgUGsKWXoSZigWpnxUwYCTDu KtfepZ6fFG7kx9UGvtoV9BjizWOSzYjKNuckFPwop/I2gqiptMw7/0KZcUL7FpFrpRwN BfiaKA1F+zKqT8PviQS7aHnc1L2N8rdYGELnBqPRv0w7KL+6/J0ixMC9xoCptggiD+aN C8WBje1njnxj/DQu5Hk+DNZB4jCPA6ru+JzZ2Spq89nftyXBFC7WZcNvkhtJW7eG6xp6 DWcAcbYCMG7TWUpqxj6TG9ZomR8cECNvwGhztQY25K6EA3jDouJZH5stpqgGsUOhKTPE P/8A== X-Gm-Message-State: AOAM5320LL1ZXZAjCXXbsj2l8ejqJbpVeyq+mAU0t6ymVJkxOFIUnzp0 OA96euqRXYdIJkWtdrHAN2vfozc2I1MB9WhJzlU= X-Google-Smtp-Source: ABdhPJxbhqa9FnlKYPe9ads46cXv/QtRH6yzLeD7LfqpLoOmX6VGy8Q0SzoujEELuo2onErHXjeYsnDJm4gsnjDTVuk= X-Received: by 2002:a17:90b:3647:: with SMTP id nh7mr8898309pjb.228.1626254165248; Wed, 14 Jul 2021 02:16:05 -0700 (PDT) MIME-Version: 1.0 References: <20210713104026.58560-1-andriy.shevchenko@linux.intel.com> <20210713104026.58560-3-andriy.shevchenko@linux.intel.com> <9af24b96-8119-7ccf-f0d0-d725af80aa0b@kernel.org> In-Reply-To: <9af24b96-8119-7ccf-f0d0-d725af80aa0b@kernel.org> From: Andy Shevchenko Date: Wed, 14 Jul 2021 12:15:25 +0300 Message-ID: Subject: Re: [PATCH v1 3/4] serial: 8250_pci: Always try MSI/MSI-X To: Jiri Slaby , Randy Wright Cc: Andy Shevchenko , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Ralf Ramsauer Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 14, 2021 at 9:55 AM Jiri Slaby wrote: > > On 13. 07. 21, 12:40, Andy Shevchenko wrote: > > There is no need to try MSI/MSI-X only on selected devices. > > If MSI is not supported while neing advertised it means device > > being > > > is broken and we rather introduce a list of such devices which > > hopefully will be small or never appear. > > Hmm, have you checked the commit which introduced the whitelist? Nope, my bad. > Nevertheless, this needs to handled with care: while many 8250 devices > actually claim to support MSI(-X) interrupts it should not be > enabled be > default. I had at least one device in my hands with broken MSI > implementation. > > So better introduce a whitelist with devices that are known to support > MSI(-X) interrupts. I tested all devices mentioned in the patch. Thanks, but I still think that blacklisting is better. All drivers I have split (or participated in splitting) from 8250_pci have enabled MSI for the entire subset they serve for. > You should have at least CCed the author for an input. Thanks. I also added Randy, who extended the list. ... > > + pci_set_master(dev); > > But bus mastering is not about MSIs. Strictly speaking it's not, but MSI won't work without DMA. > I *think* it's still OK, but you > need to document that in the commit log too. > > Actually, why the commit which added this code turns on bus mastering? -- With Best Regards, Andy Shevchenko